DISEASE CHARACTERISTICS: Histologically confirmed prostate cancer High risk as defined by any 2 of the following: Karnofsky performance status of 70-80% Lactate dehydrogenase greater than 200 U/mL Hemoglobin less than 13 g/dL Prostate-specific antigen (PSA) at least 4 ng/mL Progressive disease based on any 1 of the following: Rise in PSA level of at least 25% above baseline At least 3 determinations taken at weekly intervals OR At least 2 determinations taken at monthly intervals New or progressive soft tissue masses on MRI or CT scan Radionucleotide bone scan with new metastatic lesion(s) Serum testosterone no greater than 30 ng/mL If no prior surgical orchiectomy, castrate levels of serum testosterone must be maintained with continuation of gonadotropin releasing hormone analogs If receiving an anti-androgen, must show progression of disease after stopping anti-androgen therapy